A principled approach to REPL interpreters

L. Thomas Van Binsbergen, Mauricio Verano Merino, Pierre Jeanjean, Tijs Van Der Storm, Benoit Combemale, Olivier Barais

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

17 Citations (Scopus)

Abstract

Read-eval-print-loops (REPLs) allow programmers to test out snippets of code, explore APIs, or even incrementally construct code, and get immediate feedback on their actions. However, even though many languages provide a REPL, the relation between the language as is and what is accepted at the REPL prompt is not always well-defined. Furthermore, implementing a REPL for new languages, such as DSLs, may incur significant language engineering cost. In this paper we survey the domain of REPLs and investigate the (formal) principles underlying REPLs. We identify and define the class of sequential languages, which admit a sound REPL implementation based on a definitional interpreter, and present design guidelines for extending existing language implementations to support REPL-style interfaces (including computational notebooks). The obtained REPLs can then be generically turned into an exploring interpreter, to allow exploration of the user's interaction. The approach is illustrated using three case studies, based on MiniJava, QL (a DSL for questionnaires), and eFLINT (a DSL for normative rules). We expect sequential languages, and the consequent design principles, to be stepping stones towards a better understanding of the essence of REPLs.

Original languageEnglish
Title of host publicationOnward! 2020 - Proceedings of the 2020 ACM SIGPLAN International Symposium on New Ideas, New Paradigms, and Reflections on Programming and Software, Co-located with SPLASH 2020
EditorsStephen Kell, Didier Verna
PublisherAssociation for Computing Machinery, Inc.
Pages84-100
Number of pages17
ISBN (Electronic)9781450381789
DOIs
Publication statusPublished - 8 Nov 2020
Event2020 ACM SIGPLAN International Symposium on New Ideas, New Paradigms, and Reflections on Programming and Software, Onward! 2020, co-located with SPLASH 2020 - Virtual, Online, United States
Duration: 18 Nov 202020 Nov 2020

Conference

Conference2020 ACM SIGPLAN International Symposium on New Ideas, New Paradigms, and Reflections on Programming and Software, Onward! 2020, co-located with SPLASH 2020
Country/TerritoryUnited States
CityVirtual, Online
Period18/11/2020/11/20

Keywords

  • interpreters
  • language workbenches
  • meta-languages
  • note-books
  • REPLs
  • software language engineering

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